609-02-9Relevant articles and documents
Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)
Condon, Sylvie,Le Gall, Erwan,Pichon, Christophe,Presset, Marc,Xavier, Tania
supporting information, p. 2085 - 2094 (2021/09/02)
The use of mono-substituted malonic acid half oxyesters (SMAHOs) has been hampered by the sporadic references describing their preparation. An evaluation of different approaches has been achieved, allowing to define the best strategies to introduce diversity on both the malonic position and the ester function. A classical alkylation step of a malonate by an alkyl halide followed by a monosaponification gave access to reagents bearing different substituents at the malonic position, including functionalized derivatives. On the other hand, the development of a monoesterification step of a substituted malonic acid derivative proved to be the best entry for diversity at the ester function, rather than the use of an intermediate Meldrum acid. Both these transformations are characterized by their simplicity and efficiency, allowing a straightforward access to SMAHOs from cheap starting materials.
Visible-Light-Enhanced Cobalt-Catalyzed Hydrogenation: Switchable Catalysis Enabled by Divergence between Thermal and Photochemical Pathways
Mendelsohn, Lauren N.,MacNeil, Connor S.,Tian, Lei,Park, Yoonsu,Scholes, Gregory D.,Chirik, Paul J.
, p. 1351 - 1360 (2021/02/01)
The catalytic hydrogenation activity of the readily prepared, coordinatively saturated cobalt(I) precatalyst, (R,R)-(iPrDuPhos)Co(CO)2H ((R,R)-iPrDuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene), is described. While efficient turnover was observed with a range of alkenes upon heating to 100 °C, the catalytic performance of the cobalt catalyst was markedly enhanced upon irradiation with blue light at 35 °C. This improved reactivity enabled hydrogenation of terminal, di-, and trisubstituted alkenes, alkynes, and carbonyl compounds. A combination of deuterium labeling studies, hydrogenation of alkenes containing radical clocks, and experiments probing relative rates supports a hydrogen atom transfer pathway under thermal conditions that is enabled by a relatively weak cobalt-hydrogen bond of 54 kcal/mol. In contrast, data for the photocatalytic reactions support light-induced dissociation of a carbonyl ligand followed by a coordination-insertion sequence where the product is released by combination of a cobalt alkyl intermediate with the starting hydride, (R,R)-(iPrDuPhos)Co(CO)2H. These results demonstrate the versatility of catalysis with Earth-abundant metals as pathways involving open-versus closed-shell intermediates can be switched by the energy source.
FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
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Paragraph 0175; 0185-0186; 0292-0294, (2021/06/22)
The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
Santra, Surojit,Maji, Ujjwal,Guin, Joyram
supporting information, p. 468 - 473 (2020/02/04)
Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
“Backdoor Induction” of Chirality: Trans-1,2-cyclohexanediamine as Key Building Block for Asymmetric Hydrogenation Catalysts
Glasovac, Zoran,Kirin, Sre?ko I.,Kokan, Zoran,Opa?ak, Sa?a,Peri?, Berislav
supporting information, p. 2115 - 2128 (2019/01/04)
This paper describes the synthesis and characterization of 21 chiral monodentate ligands L, assembled of three building blocks utilizing amide bonds: a metal binding triphenylphosphine, a chiral cyclic diamine and an additional substituent for fine-tuning the steric and/or electronic properties. Cis square-planar metal complexes of RhI and PtII with ML2 stoichiometry have been prepared and characterized by spectroscopic methods (NMR, IR, UV-Vis, CD) and DFT calculations. A key feature of the metal complexes is a prochiral metal coordination sphere and “backdoor induction” of chirality from a distant chiral source via an outer-coordination sphere, well-defined by aromatic stacking and hydrogen-bonding. The rhodium complexes were used as catalysts in asymmetric hydrogenation of α,β-dehydroamino acids with excellent yield and selectivity (up to 97 % ee), strongly supporting the “backdoor induction” hypothesis.
Copper-Catalyzed Dehydrogenative Diels-Alder Reaction
Jiang, Bing,Liang, Qiu-Ju,Han, Yu,Zhao, Meng,Xu, Yun-He,Loh, Teck-Peng
supporting information, p. 3215 - 3219 (2018/06/11)
A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
2 - methyl malonic acid diester synthetic method of the compound
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Paragraph 0043-0045, (2017/08/10)
The invention discloses a synthetic method of 2-diester methylmalonate compounds, and relates to the technical field of carboxylic ester preparation. The synthetic method comprises steps as follows: C, sulfonic acid 2-ethyl N-cyanoethanimideate IV and cyanide react under the action of a solvent and a catalyst, and 2-methyl malononitrile V is obtained; D, 2-methyl malononitrile V and ROH react under the action of the solvent and concentrated sulfuric acid, and products of 2-diester methylmalonate compounds I are obtained, wherein MCN is cyanide, M is Na or K, ROH is alkyl alcohol, alkenyl alcohol or a fluoride group containing alcohol, is benzyl alcohol or benzyl alkyl, halogen or nitro substituted benzyl alcohol, or is phenol or C1-C5 containing alkyl, halogen or nitro substituted phenol. The method is unique, the reaction conditions are mild, the reaction process is basically free of by-products, the yield is high, adopted raw materials have extensive sources, and acetaldehyde can be used as the raw material; the synthetic method is applicable to industrial production.
Ester derivative industrial production process
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Paragraph 0049; 0050; 0051; 0052; 0053, (2016/10/10)
The present invention provides an ester derivative industrial production process which is characterized in that a monoester or a diester derivative is obtained by reaction of a compound A and carbon monoxide or carbon dioxide under the effect of a catalyst; the production process is simple, and is different from complex production ways and demanding production conditions in the prior art, and the target ester derivative product can be synthesized by one step. The production process and synthetic routes are optimized, so that the production process is fewer in side effects, convenient in post treatment, mild in production conditions, and suitable for industrial production modes.
Copper(II) triflate catalyzed amination and aziridination of 2-Alkyl substituted 1,3-dicarbonyl compounds
Ton, Thi My Uyen,Tejo, Ciputra,Tiong, Diane Ling Ying,Chan, Philip Wai Hong
experimental part, p. 7344 - 7350 (2012/06/16)
A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu(OTf)2 + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhI=NTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic C-H bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2-3 equiv was discovered to result in preferential formal aziridination of the C-C bond of the 2-alkyl substituent of the starting material and formation of the aziridine product.
Behaviour of enaminomalonates and enamidomalonates under various reductive conditions: a novel synthetic approach to N-acetyl-N-aryl β-amino acids
Sol?an, Tomá?,Jakubec, Pavol,Prónayová, Nade?da,Milata, Viktor
, p. 2631 - 2633 (2008/09/19)
The behaviour of enaminomalonates and their deprotection to amines under various reductive conditions is described. A new synthetic approach to N-aryl-N-acetyl-β-amino acids using heterogeneous catalytic hydrogenation has been discovered.
